v1.9.419 — rename entry file to bin/leerness.js (UR-0126)

Renamed the entry file bin/harness.js to bin/leerness.js for naming consistency with the leerness command/package. No user impact (install/run via the leerness command, unchanged). package.json bin/main/scripts + e2e/smoke/ci/docs path refs updated; __filename-based internals auto-adjust. selftest 164 to 165, e2e 418 to 419, zero regression.